Electron tube impulse generator



Aug. 24, 1948. E MUMMA AL 2,447,661

ELECTRON TUBE IMPULSE GENERATOR Filed May 26, 1943 4 Sheets-Sheet 1 Z'-GY /5v,

FIG. 1

Robert E. Mumma and Lawrence D. Kilheffer lnventqra Their ttorney Aug.24, 1948. R. E. MUN [MA ETAL ELECTRON TUBE IMPULSE GENERATOR 4Sheets-Sheet 2 Filed May 26, 1943 Robert- E. Mumma and Lawrence D.Kilheffcr Inventors Their Attorney Aug. 24, 1948. R. E. MUMMA ET2,447,661 I ELECTRON TUBE IMPULSE GENERATOR 4' Sheets-Sheet 3 Filed May26, 1943 FIG. 3

Robert E. Mumma and Lawrence D. Kilheffer Inventors y M M Their AttorneyAug. 24, 1948.

Filed May 26, 1943 FIG. 4

R. E. MUMMA EI'AL 2,447,661

ELECTRON TUBE IMPULSE GENERATOR 4 Sheets- Sheet 4 I Robcrt E. Mumma andLawrcnu: D. Kilhcffer Inventors;

MLM

Their Attorney iatented Aug. 24,

2 3414%? ELECTED GENERATOR Entrance ii. finherree; its! 'osrsut o TheNational Cash aiton; Glfib; iii cor'por'atidfi' Ar isans 1942'; steered.4881496 one" of a' iiu'rdliti 6f gas-emisel tr (cl. ere-2am mineat whattube in the tens bank the operation is fi d' lie' cemm rrceq; Thehighest denomination- :il" Bank; ifi this disclosure the hundreds bank}includes a group of gaseous triodes operated a. chain having a:beginning point and an end.

These tubes are operated step by step, each step ducting. and requiring:a cdfitroliini gfld' 5' potential of about 12 vclts'nganv' itn i "tn?the cathode. number (if full i clesl p partial cycle, if desired, the intime fifddil forfzmyoddrnumbefefimnulsesn" anner in a run cycle orcycles that r5 uire-a? flit it;

Operation 6f the keysprjgsets c am: 4'

each bank for operation: the (Sftfi I bank of tubes arecohnectedfih antiwil be ev time of the hundreds chain is fired,. the cycling 6f theunits chain is" stopped", and the operaitioii' is don'ifilete. r r V vTfiefefoie'; the firincipell object of the invention is] to iifovid'e a'novel el'e'ctr'o'n tube electric iiiifilils' generator for producing" aburst of e'lefictfri'0 ilhbiilses of unit Value and of a preciseselected" Krid'thf object of the invention is to provide anenaiessepmtive chain of lectr'oii' tubes autoffifiticelllyfiring one ata} time in s quence", cyclit'any, tinder bntforas to the number ofcycles, oliject of the invention is to provide.

w piilretlijty of g'ioups of electron tub'es, one of til" gr ups beingonetime one at a; time in endless c'ha rif sequence cyclically, and theother groups; cpntrtuin t-Yienumber of full cycles that said firstgrouper tubes onerates, as selectively piecftefnflfiedi l .7

' ether objector the invention is to: provide en nmessoperativecnam ofelectron tubes o 1- anea-tomaticauy one at'a'. time in sequence filli'r, r t h iridtiier object of the invention istopr'ovidel operativecha-i'n of electron tubes open-'- tomatt'ically one at a; time insequence;- cybli ell f'r'om=- a selected beginning point. n

2116 er ofijedt of the invention is t'o fireman an eii'dl'sschain ofelectron tubes rendered con "*dfibt g' gumm tibn one" at a time in egueneea Y to generate an electric impulse 6n a output circuit eachtii'ri'e' a tube becomes Amine object of the invention is to providedenominational banks of electron tube's'tthetulie's' entire lowesttimening automati any' rnde'f'ed iid'iibting in dless ch'ain sequence stepby step. orient genie-cynically, sa'id'cycles beln'g count 6:? and:selectively determined in number by (iteration 0t tlie'higherdendrnifialtibnai mints-f of" tubes?" Aii'dtlier sweet of the-inventionis to provide 1t'-' pliii lity of denominational groups of electron athe tubes at one groupbemg-operated s'e"-" qiie'iitifilly to produceimpulse and cyclically t0 sentials of which are set forth inappendedclaims and a preferred form or embodiment of which hereinafterdescribed with reference to the drawings which accompany and form a partof thisspecification.

Of said drawings:

Fig. 1 is a circuit diagramoi the operation: a

initiating electron tubes. Fig. 2 is a circuit diagram of the units bankof the impulse generator and the output impulse power tubes, with amiddle portion of the bank omitted.

Fig. 3 is a circuit diagram of the tensbank of the impulse generator,with a middle portion of the bank omitted. v

Fig. 4 is a circuit diagram of the hundreds bank of the impulsegenerator, with a middle portion of the bank omitted.

Initiation of an Operation shock application of potential to conductor26' Starting tube receives its anode potential from conductor 26 throughresistor 29 of 100,000 ohms, point 30, and resistor 43| of 5,000' ohms.Point 30 is coupled to conductor 26 by a capacitor 3| of .0005microfarad to provide an initialhigh current as tube 20 fires andbecomes conducting. The"cathode'of tube 20 is connected to groundthrough resistor 32 of 25,000 ohms. The grid of tube 20.is connected toconductor 33 supplied with 150 volts negative potential, from source 34,through resistor 35 of 500,000 ohms, points 36 and 31, and resistor 38of 1.5 megohms, which makes the grid highly negative before. switch 25is closed. Point 3! is connected to conductor 26 through resistor 39 011 megohm, and point 36 is coupled to negative 150 volt conductor 33through capacitor 40 of'.02 microfarad. Consequently, when switch 25 isclosed, capacitor 3| becomes charged before the larger capacitor 40, andfinally, as the point 36 becomes more and more positive, tube 20-fires,and the momentary ,highcurrent through the tube due to capacitor 3|causes the cathode to deliver, due to cathode resistance 32, a sharppositive impulse at point 4|. This impulse fires a tube 2|, the firingtime of which is used for delay purposes. Tube. 2| receives its anodepotential from conductor 26 through resistor 42 of 1,000 ohms, point 43,and resistor 44 of 1,000 ohms.

The cathode of tube 2| is coupled to ground through resistor 45 of25,000 ohms in pa l with capacitor 54 of .004 microfarad and isconnected to negative supply conductor 33 through resistor 46 of 50,000ohms 'andresistor41 of 120,000 ohms, giving the cathode a normalpotential of about 19 volts negative. Point 48, which determines thenormal potential-0f the grid of. tube 2|, is connected to ground byresistor 49 of 40,000 ohms and is connected to the negative.

ill

conductor 33 through resistor 50 of 100,000 ohms, giving point 48 anormal potential of about 43 volts negative, which will maintain tube 2|nonconducting until point 5| receives the positive impulse from point 4|through coupling capacitor 52 of .00005 microfarad, which fires tube 2|.Grid resistor 53 is oi 5,000 ohms. Af,te r delay capacitor 54 ischarged; as itube1 2| b'ecomesconducting, point 55 rises in'potential,due to the effect of resistor 45, which rise in potential is reflectedat point 56, which determines the grid potential Tube 22 receives itsanode potential from point 43, beforeflde'scribed. Its cathode isgrounded throughresistor 58 of 50,000 ohms in parallel withcapacitorflll of .QOI microfarad. The grid of tube 22 is at the normalpotential of point 56, which is madeabout57 volts negative. Thus, tube22 is held from firing until its grid potential is raised bythe firingof tube 2| and its continued conduction until delay capacitor 60 of .004microfarad is charged. Grid resistor 6| is of 500,000 ohms. As tube 22fires; a sharp positive potential impulse is produced at point 62 afterdelay capacitor 59 of .001 microfarad is charged. The impulse a'tpoint62 is conveyed through capacitor 63 of .00005 'microfarad to point 64 tofire tube 23, which may or may not fire according to whether an extraunit is to be entered in the tens order of the impulse generator.

v The cathode of tube 23 obtains its potential through point 65 (seealso Fig. 2), point 66, conductor 61, and point 68, which is the cathodesupply point for tube 69 in the units bank Conduction in tube 23(Fig. 1) will therefore cause a change in'the potential of point 68(Fig. 2) just as though tube69 were conducting. This rise in potentialof point 68 is to be observed later in connection with the descriptionof the entry of the extra unit. Point 68 (Fig. 2) is also connectedthrough terminal point 65'to the input conductor 110 (Fig. 3) of thetens order of the impulse generator for entering an extra unit into thetens order, as will be explained. v

Point 62. is also coupled through terminal 10 (Figs. 1 and 2), point 1|(Fig. 2), and capacitor 12' of .00005 .mic'r'ofarad to grid 'point 13,the change in potential of which fires tube 14 whenever tube 22,(Fig. 1) fires. Point 1| (Fig. 2) is givenja normal positive'potentialby being connected through resistor 15 of 50,000 ohms, point 16(see alsoFig. 4), the lower key switches of the hundreds key bank, point Ti (seealso Fig. 3), the lower key switches of the tens key bank, point 78 (seealso Fig. 2), and the lower key switches of the units key bank to point19, which connects to the -volt positive supply source 80. So, when nokey is operated in any bank,,thecath0de of tube 22 (Fig. l) is held sopositive that it will not fire, thus preventing impulses frombeinganomalousy generated. The depression of any key will remove thepositive potential from the cathode of tube 22.

'Theinormaligridbias of tube 23 (Fig. 1) is obtained from' point 8|,which is connected to ground through resistor 82 of 30,000 ohms andconnected to the -volt negative conductor 33 through resistor 83 of100,000 ohms, thus giving the said point BI and the grid a resultantnegative potential of about 34 volts with respect to the cathode. Thenormal grid bias of tube 74 (Fig. 2) is also obtained from point 8|(Fig. 1) through terminal point 84 (see also Fig. 2), resistor 85 of250,000 ohms, and point13.

Thus, tubes 20,- 2|, 22 and 23 fire in succession a r-macs when startingkey: switclr. 25' is. closed, exceptv that whom no denondnattpnalzkeyis. depressed; onlyr tubes: 20 and; anez fired; and exceptiwlren, a keyis. operated; in; the units; bank in which: event only.- tubesalfl; 21;and 221 arefired, since, as, laterexplained, tube 23:- is deprived: ofanode: potential: when a key.- is. depressedz' in the units banle. i

The positive impulse which appears. on: termie nab 81' (Fig... It) astube: Zfiflres; is used: to prepare the tens and hundreds banks of:thehdeviceforoperation, it being obviouslynecessary tothave these banksreadygbeiorethe: operationlofl the units: bank begins. The: positivepotential? imapulse; on terminalkpoint ll, as tubelkflrcs, int;-tiatesthe operationdmthe units-bank. The cur rent flowthrougln point;55: causes; the entering ofianextraiupit of: datau-into the device andW-heIE-DEGBSSBIY; s

The units bank of' the device includes elevengaseoustriode-electrontubes, one of which; tube L4; participates only in the initiation of thecyclic operation; The remaining ten" or the tubesare connected in anautomatic operative circuit whereby-theyare firedone at a time sequencein an endless ohairrcycle: As any 'one' of'theeleven tubes-is rendered-cenducting an output" impulse is generated; the total number-of whichoutput impulsesebeing'ctheend result ofthe operation of the device. Theten tubeswill bedesignated by the terms first, seeond; third, tour-thyorang si xttp sev'enth,- eighth,-"* nintlul andWtent-ln the tubesintermedia-te the second and n-i'ntlo notbeing shown, as they wouldzonly uselessiyi the circuit drawin'gsiwith repeating -'pa,ttr i 1.- Thedesignations; ot thes-tubes in this unitsbank orthe tensancl zhundredsbank; are-notzne'cessarily digitsvalues, but: merel c-representth'eiriordeninithci end less'chainr i The: anodes ot; the tubesaof teiendlesszzchain. andzetubez I4; constituting thesunitsbaink receive: asllb volt; positivezsupplyzby commonly: connccfi iir to; conducton 90;which: is; connectedi throu resistor 5'12: f; LQ00i0hm8s 199ml 52 and;stor 9? 0131 3.00 ohms 1'. ton supplyr terminal .80;: Point this coupledto groundby capacitonflaof microiarad,- which, absorbs 3513.001?applications:

ot potential andastabilizes. the potential-50f point 9.2;

lib-volt negative supply conductor .98ithrougli a:

150,000- ,ohm resistor,,like resistor 9'9;- a..point,,l'ik'e point I90,and .a 300,Q00-ohm, resistomlikeresister lliil. Thisigives thecathodeseacha potentialiof about ei'eyolts negative when non-conducuing'; Points like point; IOUhave a normal;poten.- tial; when theassociated'cathode is non-conduct; mg, cffaboutsit'volts ne ative and"are connected; topthe control" grid off'the next succeeding tube of the;chain,, asthrough': a point "like l02""and a" resistor: of Q0100d1ohm-s 'lik'e'resistor' Hi3: The" conductor I'M completes the couplingor'the' The: gridpoteritiahsupply for :tube, 'lLhas.-

tentl'rf tube-to the firstd'tubeto close the chain. amendlesscha'inoAsa-tube of: the endless chain of the. unitsv banlccommences: toconduct, thecapacitor" coupling: its cathodeto' ground charges,preventing the. immediate rise of its cathode potential due totheresistances in the cathode-supply circuit. During the first interval ofchargingzoi the cathode-ground capacitor; the conductor drops inpotential towithin about 22fivolts-ofground. Every'other tube ofthe'chairi is connected to' the anode supply conductor 90 and; if anytube iscOnducting, it will thereuponbe extinguished, as itscathode-ground capacitor has therefore been charged, which maintainsthecathode at highpotential as the anode poten-- tial drops and'overshootssuch maintained poten-- tial ofthe cathode; Such extinguishing actionisexplained'more fully in-United States application for Letters Patent,Serial No.- 395,995; filed May '31, 1941, by Robert Ei-Mumrnawhich-issued Jun-e4; 1946,- as- U'; S. Patent No. 2,401,657.

As a tube of the endless chain of tentubes inthe units bank of thedevice becomes conducting and its cathode-rises inpotential after thecathode-ground"capacitor is charged, the point correspondingto pointlilllwill rise in potential sufiiciently to'cause'-th -grid' ofthesucceeding tube of the chain to fire: Consequently, the tubes in theendless-chain of tubes will be rendered conductingone at a time insequence as long as the operation is not stopped. Negative impulseswi-ll-be produced and conveyed to point through capacitor [06 of .00025microfarad'; each time a tube'of' the chain becomes conducting.

- Conduction in tube 14 also causes an impulse at point I05:

The stopping of the operation of the endless chain of the units'bankis'done by impressing terminal lfl'l with a" strong negative potentialto prevent'theffirst" tube from being fired by the tenth tube; andyasan'object of the inven-- tion is 'to-provide means to produce a numberof impulses precise totheunit, the endless chaino'peration must be begunat a selected tube and sto at afixedpoint; which will cause the de--vice to produce an exact number of impulsesto'" represent the unitsorder.- To this end, selecting keys, operating switches, determine wherein the chain-the operation shall commence. Point l l l is the fixed:point for stopping the endless: chain operation; Each key is given avalue characterization Which-tells the number of impulses that will besent in a first partial cyclej before-the first tube is fired to start afullcyc1e,- if'such key is operated.

The keys are-numbered 9, 8, 7;"6;' 5; 4 3,"2,'" and 1, the keys in thedes'cending series-between 9 and 2 not being shown for the reasons givenbefore in connection'withtheintermediate tubes of the endless chain thatare not shown.

As-nn example; if the- 9 key 'of the units bank-is operated; switch-I08moves to its lower contacts, breaking the connection from point' 'l9tdpoint' 'l8 -(sce' also'Fig. 1), thus depriving the" wwanthejcathode'of tube secondl As tube 22' '(Fig, 1 fires after closingstarting 'key switch 25 a positive impulse appears at point 'IU-(s'ee'alsoyFigi; 2) which fires tube 14 to give thefirst' output-impulse-onconductor 905' It' will be ob served that the cathode of tube 74receives its potential from the cathode. of tube second," due to theswitching of switch I09 of the 9"- key to the lower contacts. The effecton point H is to raise its potential as though the "second tube wereconducting, which results in the tubes "third, fourth, fifth, sixth,""seventh? eighth," ninth, and tenth firing before the operation of theunits bank can be stopped. It will be evident that nine impulses willhave been produced after the firing of the tenth tube. In the samemanner, operation under control of the 1 selecting key permits only tube14 to fire before the operation of the units bank can be stopped byplacing a stopping potential on terminal I07. As the tenth tube fires,the positive impulse appearing at point 68 is impressed through terminal65 (see also Fig. 3) to the input conductor of the tens bank of thedevice, which is thereby operated a step at the completion of each fullcycle or part cycle of the units bank.

In the event that no key is operated in the units bank, tube 14 firstoperates, and tube second" is fired by the subsequent rise in potentialat point Hi. In addition, the extra unit tube 23 (Fig. 1) is suppliedwith anode potential, which causes it to fire simultaneously with tube14 (Fig. 2), and, through connection of its cathode with the cathode oftube tenth of the units bank, the common point 55 leading to the inputof the tens bank (Fig. 3) is given an extra impulse. Therefore, if nokey is operated in the units bank, an extra impulse is supplied to thetens bank.

Power amplifier electron tube I20 (Fig. 2) is provided to amplify andconvert the negative output impulses appearing at point I05 intopositive impulses at terminal I22, and power amplifier electron tube l2iproduces amplified negative impulses at terminal I23. 7

Thus, the odd units impulses, produced in the first partial cycle of theunits chain of tubes, are

selected by key switches characterized by a like number. Full cycles ofthe units bank give ten. impulses each.

The tens bank .The tens bank (Fig. 3) of the device includes anauxiliary gaseous triode 200 and ten gaseous triodes connected in anendless counting ring operated step by step in response to impulses, oneimpulse causing one step of operation. There are shown in Fig. 3onlythree tubes of the ten tubes-the first, the ninth, and the tenth. Tubessecond, third," fourth," fifth, sixth, seventh, and eighth are not shownfor the same reasons given for deletion of some of the tubes of theunits bank.

All of the tubes of the tens bank receive their anode potential of 115volts positive from conductor 20! through 3,000-ohm resistor v202, point203, and resistor 254 of 300 ohms. Capacitor 205 'of microfarad,coupling point 203 and ground, acts as a shock absorber and stabilizerin the application of potential to the tens bank. The cathode of eachtube of the ring is connected to ground through a 15,000-ohm resistor,like resistor 206, in parallel with a. resistor of 1,000 ohms, likeresistor 201, in series with a capacitor of .004 microfarad, likecapacitor 208, and is connected to the negative 150-volt conductor 209through a resistor of 100,000 ohms, like resistor 2l0, a point, likepoint 2| l, and a resistor of 100,000 ohms, like resistor 2I2. Un-

der these circumstances, a cathode is normally at about 10 voltsnegative when-non-conducting. The potential of the associated grid isnor.- mally held at about 87 voltsnegative, thus holding the tube innon-conducting condition. The grid of each tubeof the tens .chain iscapacitatively coupled to input conductor.'ll0 and terminal 65 from theunits bank through a capacitor of .0005 microfarad, like capacitor 2l3,a point like point 2, and a current-limiting resistor 01 500,000 ohms,like resistor 2|5. Resistors corresponding to resistor 2l6 are of500,000 ohms.

' When tube 20 (Fig. 1) fires, a positive impulse is impressed throughterminalfll (see also Fig. 3) and capacitor 2|! of .00005 microfarad topoint 2IB, which is connected to the grid of auxiliary tube 200 throughresistor 2l9 of 50,000 ohms. The grid of tube 200 is normally suppliedwith a potential of about 34 volts negative, being connected to point220 through resistor 22! of 250,- 000 ohms, which point 220 isconnectedthrough resistor 222 of 30,000 ohms to ground and through resistor 223to the -volt negative conductor 209. The cathode of tube 200, when notens key is operated, takes its potential from point 225, which is 10volts negative, or is given the same potential by being switched by theupper key switch when a tens key is operated, like, for instance, the 9switch 226, to the cathode of the associated tube, which in the case ofswitch 226 is the first" tube. Consequently, normally nonconducting tube200 is caused to conduct at the commencement of an operation by theclosing of switch 25 (Fig. 1) and the ensuing conduction in tube 20,which produces the positive pulse to fire tube 200 (Fig. 3). As tube 200fires, it changes the cathode potential of the cathode to which its owncathode is connected, in a positive sense. Thus, if the 9 key wereoperated, point 230 of the cathode of the first tube would be causedtorise in potential, which rise would be transmitted in part to the gridof the second" tube to bring said second tubes grid potential highenough so that a, positive impulse impressed on input terminal 10 wouldfire the second" tube. In the event that no key of the tens bank isoperated, the tenth tubes cathode is raised in potential as tube 200fires, and, on the receipt of the first input impulse, the first tubefires;

This first impulse may come either from the firing of tube 23 (Fig. 1)or from the firing of units bank tube tenth of Fig. 2. The rise inpotential of the cathode of the tens bank tenth tube as it fires isconveyed to the grid of the first tube by conductor 221 to complete thering. Each time the first tube of the tens bank is fired, a positivepotential impulse is sent through terminal 338 to the hundreds bank(Fig. 4) to operate it a step from its preset condition. The tens bank,then, operates a step for each impulse received on terminal 10 andtransmits an impulse to the hundreds bank to operate it a step each timethe cathode of the first tube of the tens bank rises in potential.

By operating a selected one of the digit keys 1" to 9 in the tens bank,it may be determined that the first cycle of the tens bank shall be lessthan a fullcycle and by how many steps. Thus, if the .lfkey, wereoperated in the tens bank, the firing of tube 200 would cause the tenthtube grid to be primed to fire said tube on receipt of the first impulseon terminal 10, and, on receipt of the second impulse, the first tubewould fire, sending atransfer impulse to the hundreds bank.

The hundredsbcmlc The hundreds bank (Fig. 4) of the device in: cludesten gaseous triodes interconnected into an operative chain in which thetubes are caused to fire one after another from a selected beginningpoint to an end point in the chain.

These tubes are designated in Fig. 4 as first ninth, and tenth, theintermediate tubes second, third, fourth, fifth, sixth', seventh, andeighth not being shown for the same reasons stated in connection withsimilar deletions in the other banks previously described;

The ten tubes of the chain are given 115 volts positive anode potentialthrough conductor 300, resistor 30l of 4,000 ohms, point 302, andresistor 303 of 300' ohms, which is connected to the H5- volt positivesupply terminal 304. Point 302 is coupled to ground throughshock-absorbing and stabilizing capacitor 305 of .1 microfarad.

The cathodes of each of the tubes of the chain, except the first tube,are connected ,toground through a 15,000-ohm resistor, like resistor306, in parallel with a capacitor of .004 microfarad, like capacitor301, and are connected to-the negative l50-volt potential supply,conductor 308 through a resistor of 100,000 ohms, like resistor 309, apoint, like point 310,.and a resistorof 100,- 000 ohms, like resistor 3|Pointslike point 3I0 are connected through a resistor of 500,000 ohms,

like resistor 3l2, apoint, like point 313, and a resistor of 50,000ohms, like resistor 3l4, tothe grid of the tube of the series having thenext higher designation. Each point corresponding topoint 3l3 isconnected to'impulse input conductor 3|5, energized from the tens bank,through a .00005- microfarad capacitor, like capacitor 315. The secondtube grid (not shown) issupplied with biasing potential through a point,3l1, which obtains its potential from thepotential-dividing resistances3l8, 3l9, and 320, which are of-the same values, respectively, asresistances 300,309, and

The cathode of the first, tube ,of the hun-' dreds bank is normallyconnected by means of conductor 322, point 323, and c1osed switches ofthe upper key switches, like switch 324', when no key is operated, tothe cathode ofthe tenth tube. However, as a key, like 9, is operated,the upper switch 324 breaks the connection to the cathode of the tenthtube and establishes it by way of conductor 325, lowered switch 324, andconductor 326, through resistor 3! to priming point 311 leading to thegridof the second tube (notyshown); Operation of the 1 key instead ofthe 9 key connects the cathode of the first tube by way of conductors325 and 321 to the cathode oithe ninth tube.

Thus, when the operation oi the hundreds bank:

is commenced by a positive impulse impressed on terminal 81 (seealsoFig. 1) as tube 20 fires, the

first tube (Fig. 4.) of the: hundreds bank be'- comes conducting, and,by reason of the switching connections, just explained,-when a key isoperated, the cathode supply of said first tube tive, and the grid is'givena-normal potential of about 5'7 volts negative byreasonotbei'ngconnected to ground through 30,000-ohm'r'e sistor 330, and beingconnected to the negative 150-vo1t supply conductor 308 through resistor33| of 100,000 ohms. Resistors 332 and 333 are, respectively, of 250,000ohms and 50,000 ohms, This grid potential holds said first tubenonconducting until the starting impulse is received at terminal 81,which is conveyed through capacitor 334 of .0005 microfarad and resistor333 to fire said first tube. If no key is depressed, the firing of saidfirst tube acts on point 335 just as though the tenth tube had fired. Ifthe one key is depressed, the firing of the first tube acts on point 330as though the ninth tube had fired, priming the grid of the tenth tube,and so on, theoperation of the 9 key causing a potential rise at thegrid point 3l1 of the second tube.

The operation of the device is stopped by the firing of a stop tube 331,which is fired by the first impulse received from the tens bank afterpoint 335 has risen in potential due either to conduction in tube tenthor conduction in tube "first when no key is operated.

Therefore, when no key is operated in the hundreds order, the firstimpulse received from the tens bank through terminal 338 stops thegeneration of impulses, in 'a manner to be explained. If the 1 key ofthe hundreds bank is operated, the generation of impulses will bestopped on the second impulse conductor 315 received from the tens bank.

The chain-connected tubes of the hundreds bank are rendered conductingone at a time, as the firing of any tube in the chain extinguishes anyother conducting tube therein because of the momentary dip in thepotential of anode supply conductor 300 as a tube, supplied thereby,fires.

Termination of operation Stop tube 331 receives its anode supply throughresistors 340 and 341 of 300 ohms and 10,000 ohms, respectively,connecting it to the 115-volt positive conductor 308, and throughresistors 342 and 343 of 75,000 ohms and 120,000 ohms, respectively,connecting it to the negative supply conductor 308. This gives the anodeof tube 331 a normal anode supply of about 103 volts positive and givespoint 344 a normal potential of about 5 'volts' positive. The cathode oftube 331 is normally about 10 volts negative, resistor 350 being of3,000 oh-ms and resistors 35! and 352 totaling 40,000 ohms. The grid ofthe stop tube is normally kept at about volts negative by beingconnected at point 380 to the negative supply conductor 308 throughresistor 315 of 100,000 ohms, and connected to ground through resistor316 of 100,000 ohms and resistor 311' of 15,000 ohms.

Therefore, when tube tenth is conducting ('ortube first is conductingand no key is depressed), which condition primes the grid of tube 331 tobe responsive to the next impulse from the tens bank and such impulse isreceived, 65'

tube 331 will fire and cause point 344, normally maintained at about 12volts, to drop sharply in potential, which drop is impressed throughrectifier 350, as has been said, on terminal I01 (see also Fig. 2),stopping the recycling of the units bank. Tube 331 is extinguished bythe opening of starting switch 25 (Fig. 1).

Rectifiertube '360 (Fig. 4) is placed in series between point 344 andterminal I01 to permit a negative change in potential to be conveyed tothe --first"tube of the units bank, but isolates its grid from apositive change in potential of the cathode of tube 331 (Fig. 4).

Operation Let it be supposed that one hundred and sixty-one impulses areto be produced. The 1" key in the units bank, the 6 key in the tensbank, and the 1 key in the hundreds bank are operated, and the switch 25(Fig. 1) is closed. The hundreds bank first tube (Fig. 4) is fired,which raises the potential of point 336; the tens bank fourth tubecathode is raised in potential at the same time by the firing of tube200 (Fig. 3) and, later, the cathode of the tenth tube 69 (Fig. 2) israised in potential due to the firing of tube 14. The cathode impulsefrom tube 14 is also conveyed to terminal 65 (see also Fig. 3) by theswitching of the I key to fire the fifth tube in the tens bank. At thispoint, one impulse has been generated at point I05 (Fig. 2). The firsttube of the units bank then fires, and the first full cycle of the unitsbank is begun, which cycle, when completed, has produced ten moreimpulses and a transfer impulse to the tens bank to fire the sixth tubetherein. The units bank cycles five more times, producing fifty moreimpulses, or a total of sixty-one impulses, before the first tube of thetens bank is fired, sending an impulse to terminal 338 (Figs. 3 and 4)to fire the tenth tube in the hundreds bank. The units bank recycles tenmore times, causing ten transfers to the tens bank and one transfer tothe hundreds bank to fire the stop tube. This produces a total of onehundred and sixty-one impulses.

Supposing, in the example, only one hundred and sixty impulses weredesired. The hundreds and tens bank-s would be preset as before, but inthe units bank, as no key is operated, point HI (Fig. 2) receives therise in potential, firing the second tube to start a complete cycleimmediately. Tube 14 firing takes the place of the first tube firing insuch first complete cycle. As no key is operated in the units bank, tube23 (Fig, 1) fires and sends an impulse to the tens bank, as has beenexplained, at the same time tube 14 (Fig. 2) fires. When no key isoperated in either the unit bank or the tens bank, the impulse from tube23 (Fig. 1) fires the first tube of the tens bank, which transfers oneimpulse to the hundreds bank.

It is apparent that the banks maybe increased in number by addingintermediate banks similar to that shown in Fig. 3. It is also apparentthat the banks themselves may vary; thus the first bank might be on abase of ten digits and the second bank on a base of five digits. Theinvention contemplates such variations.

It should be explained that timing capacitors, like capacitor 91a (Fig.2), each of .002 micromicrofarad, connect the grid of each tube of theunits bank to the 150 volt negative conductor 98, to provide a timeinterval between the firing of each two adjacent tubes in the unitsbank, to make that bank operate slower than the tens and hundreds banks.This is to provide a time interval long enough to create and apply astopping impulse to point I01, when that condition of the device isreached, without any danger of an extra unwanted cycle of the unitsorder bank. With circuit elements of the value given, the units bankoperates at 3000 to 4000 steps per minute and the tens and hundredsbanks operate at about 200,000 steps per minute. There is, therefore,time for a great number of tubes to operate in the higher orders, tobring about the stopping potential, while the first tube in the unitsorder is getting ready to fire. Although there is enough of a safetyfactor in the device, adjusted as disclosed, to accommodate anycommercially desirable number of denominational orders without danger ofan anomalous units cycle, it will be apparent that the size of thetiming capacitors, like capacitor 91a, may be increased to still furtherslow down the units bank, if it is desirable or necessary.

While the form of the invention herein shown and described is admirablyadapted to fulfill the objects primarily stated, it is to be understoodthat it is not intended to confine the invention to the form orembodiment herein disclosed, for it is susceptible of embodiment invarious forms all coming within the scope of the claims which follow.

What is claimed is:

1. In combination, means including a plurality of gaseous dischargeelectron tubes, including a designated tube, connected in an endlessoperative chain circuit wherein they automatically become conducting oneat a time serially in cycles and produce an electric impulse as eachtube is rendered conducting; means to start an operation at a. selectedtube in-the endless chain cycle; and automatic means to stop suchoperation after a selected counted number of cycles measured from thedesignated tube.

2. In combination, an electric impulse generator which, when started,continuously produces a plurality of like impulses in each of recurringcycles, each cycle being indicated by a cyclic impulse; means to countthe cyclic impulses up to a selected number; means to start thegenerator at a selected point in a cycle; and automatic means to stopthe generator when said selected counted number of cyclic impulses hasbeen counted.

3; In combination, an electric impulse generator including a. pluralityof electron tubes rendered conducting one at a time serially in anendless chain having recurrent cycles of operation, the act of a tubebeing rendered conducting causing an electric impulse; a selective keycontrolled device for initiating the operation of the generator with anytube of the chain; a. second plurality of electron tubes renderedconducting serially, one step of serial operation being caused at theend of each cycle or part cycle of operation of the impulse geenrator;and means rendered effective at the end of a compete operation of saidsecond plurality of tubes for stopping the cyclic operation of theimpulse generator.

4. In combination, an electric impulse generator including a pluralityof electron tubes rendered conducting one at a time-serially in anendless chain having recurrent cycles of operation, the act of a tubebeing rendered conducting causing an electric impulse; a selective keycontrolled device for initiating the operation of the generator with anytube of the chain; a second plurality of electron tubes renderedconducting serially, one step of serial operation being caused at theend of each cycle or part cycle of operation of the impulse generator;means rendered effective at the end of a complete operation of saidsecond plurality of tubes for stopping the cyclic operation of theimpulse generator; and selectively operable means for starting theoperation of. said second plurality of tubes at a selected. Place in acomplete operation of the tubes answer :so astoaccuratelydetermine-thenumber of comapletecycles ot operation which'shall be performed :by the firstlgroup of tubes. '7

.5. Auself-operating ring of electron .tubes .wherein the :tubes arerendered conducting one at a time in endless chain repeating cycles; anda-second operative ring of electronjtubes arranged .in an endless chainoperating .circuitwherein the tubes are caused to be rendered conductingstep .by step one at a time in endless chain repeating cycles, one stepof operation being caused by .the completion of a cycle of theself-operating ring.

6. A self-operating ring .of electron tubes wherein the tubes .arerendered conducting one at a time in endless chain repeating cycles; asecond operative ring of electron tubes arranged in an endless chainoperating circuit wherein the tubes are caused tobe rendered conductingstep by step one at a time in endless chain repeating cycles, one stepof operation-being caused by the completion of a cycle of theself-operating ring; and a third operative ring of electrontubesarranged in an ending chain circuit wherein the tubes are caused tobe rendered conduct- :ing step bystep one at a time, one step ofoperation being caused by the completion of a cycleof thesecondring. r eV 7. A selfaoperating ring:'of electron tubes :wherein the tubes arerendered conducting one at :a time in endlesschain repeating cycles;:asecond operative ring of electron tubes arranged in an endless chainoperating circuit wherein the tubes are caused to be rendered conductingstep by step one .at a time .in endless chain repeatingcycles', one stepof operation being caused by the completion of a cycle .of theself-operating ring; and selectively operable means .to preset each ringto commence the cycle of each at a predetermined tube in the ring.

8. A plurality of gaseous electron tubes each having at least an anode,a cathode, and a control grid; circuits including a common resistancefor supplying anode potential to said tubes; circuits including aresistance and capacitance in parallel for supplying cathode potentialto each of said tubes; circuits for supplying normally controlling biaspotential to the grids of said tubes, each of which grid circuits isalso connected to the cathode of another tube to form an endlessoperative chain wherein, if one preceding tube is rendered conducting,the next succeeding tube of the chain is automatically renderedconducting and the preceding tube is extinguished, said anode supplymeans being given a potential surge when a tube commences conducting;selectively operable control means for stopping the endless chainoperation at a fixed tube after a precise selected counted number ofcomplete cycles of operation of said chain, considering said fixed tubeas the end point of a cycle; and control means for starting operation ofthe device with any selected tube by causing it to conduct.

9. A plurality of electron tubes; means connecting the tubes in acircuit wherein they are rendered conducting one at a time in endlesschain sequence automatically; means to select the tube with which thesequence is started; and electronic counting means to determine acounted number of complete chain sequences performed as reckoned from afixed tube in the chain.

10. A plurality of electron tubes; means connecting the tubes to becomeconducting one at a time in an automatic endless chain sequenceoperation and tozgenerate an electric impulse each time atube becomesconductingand to generate a control electric impulse 'when a certainsequence (and tube becomes-conducting; means to count the controlimpulses; and means to automatically .stop the chain sequence operationafter :a. certain counted number of control impulses have been-counted.

L1. :In combination,- a first plurality of gaseous electron tubes, eachhaving at least an anode, a cathode, and :a control grid; meansincluding a common resistance in a common potential sup-- plyocon-ductor supplying anode potential tothe anodes of said tubes; meansfor supplying catho'de'potential to said :tubes including aresistanceandcapacitance in parallel for each cathodesupply; 111681115 supplyingnormally controlling potential bias to each grid; means connecting thetubes in an endless operative chain cathode to grid, the potentialsupply, resistances, and capacitances being so balanced that, if anyonetube is fired and rendered conducting by flower,- ing its potential grid-:bia;s, the succeeding tube in the chain will -fire and the tubes willautomatically become conducting one at a time in sequence cyclically andeach of the tubes, when commencing to conduct, causing a potential dropin said common anode supply conductor; an auxiliary gaseouselectron tubehaving at least an anode, a cathode, and a control grid, whose anode isconnected to the common anode supply conductor, whose cathode isselectively connectable to the cathodeof any tube of the ringpand whosegrid is normally given a controlling potential bias; means to relievethe grid bias on said auxiliary tube to fire it and render itconducting; a second plurality of .gaseous electron tubea each having atleast an anode, a cathode, and a control grid; means including a comm-onresistance in a common potential supply conductor supplying anodepotential to said second plurality of tubes; means supplying cathodepotential to said second plurality of tubes, including a resistance andcapacitance in parallel for each cathode supply; means supplyingnormally controlling potential bias to each grid of the second pluralityof tubes; means connecting the second plurality of tubes in an endlessoperative chain cathode to grid, the potential supply, resistances, andcapacitances associated with said second pluraltiy of tubes being sobalanced that, if one tube be rendered conducting, it will lower thepotential bias on the grid of the next succeeding tube of the chain to apoint where it is appreciably nearer the firing point than any othertube of the chain; means electrostatically coupling the grid of eachtube to the cathode of one of the tubes of the first-mentioned pluralityof tubes; a third plurality of gaseous electron tubes, each having atleast 'an anode, a cathode, and a control grid, and having anode,cathode, and grid bias potential supply means similar to said secondplurality of tubes and having operative connections between the cathodeof one tube and the grid of a succeeding tube in an ending chain from abeginning tube; means capacitatively coupling all the grids of saidthird plurality of tubes, except the beginning tube, to the cathode of atube of the second plurality; means to select for firing one of thetubes of the third plurality as a precedent to the firing of theauxiliary tube of the first plurality of tubes; and means operated bythe conduction in the last tube of the chain of the third plurality oftubes to place a controlling potential bias on the grid of one ofthe-tubes of the first plurality of tubes to stop the endless operationof said first plurality of tubes.

12. Incombination, a plurality of two or more electron tubes; means forsupplying operating electric potential to said tubes; means connectingthe tubes in an endless operative chain in which they become conductingone at a time in sequence automatically over and over; and a conductorcommon to all the tubes which is given an electric impulseas aconsequence of each tube operation.

13. In combination, a plurality of electron tubes connected in a circuitso that they become conducting one at a time in an endless operativechain automatically; selective means to determine What tube in saidchain shall be the first to become conducting; and electronic meansoperable to stop said endless chain operation at a fixed place in thechain.

14. In combination, a recycling electronic electric impulse producerproducing a fixed number of impulses each complete cycle; selectivemeans operable to cause a partial first cycle producing a number ofimpulses less than the fixed number, after which full cycles ofoperation are performed; and an electronic counter preset to stop saidimpulse producer after a selected number of cycles in addition to anyselected partial cycle.

15. In combination, a plurality of gaseous electron tubes each having atleast an anode, a cathode, and a control grid; means including a commonressitance in a common potential supply conductor supplying anodepotential to the anodes of said tubes; means for supplying cathodepotential to said tubes including a resistance and capacitance ,inparallel for each cathode supply; means supplying normally controllingpotential bias to each grid; means connecting the tubes inan endlessoperative chain cathode to grid, the potential supply, resistances, andcapacitances being so balanced that, if any one tube is fired andrendered conducting by lowering its potential grid bias, the succeedingtube in the chain will fire and the tubes will automatically becomeconducting one at a time in sequence cyclically and each of the tubes,when commencing to conduct, causing a potential drop in said commonanodesupply conductor; an auxiliary gaseous electron tube having at least ananode, a cathode, and a control grid, whose anode is connected to thecommon anode supply conductor, whose cathode is selectively connectableto the cathode of any tube of the ring, and whose grid is normally givena controlling potential bias; and means to relieve the grid bias on saidauxiliary tube to fire it and render it conducting.

ROBERT E. MUMMA. LAWRENCE D. KILHEF'FER.

REFERENCES CITED The following references are of record in the file ofthis patent:

. UNITED STATES PATENTS Number Name Date 1,932,589 Holden Oct. 31, 19331,972,535 Page Sept. 4, 1934 2,021,743 Nicolson Nov. 19, 1935 2,099,065Holden Nov. 16, 1937 2,136,621 King et a1 Nov. 15, 1938 2,146,862Shumard Feb. 14, 1939 2,158,285 Koch May 16, 1939 2,232,541 Levoy JrFeb. 18, 1941 2,303,016 Blount Nov. 24, 1942 2,303,453 Gulliksen Dec. 1,1942 2,319,333 Logan et al. May 18, 1943 2,373,134 Masonneau Apr. 10,1945 2,381,920 Miller Aug. 14, 1945 FOREIGN PATENTS Number Country DateGreat Britain Aug. 24, 1931

